Re: building rc on QNX4

["Smarasderagd" <smarry@vex.net>]

Chris Siebenmann <cks@hawkwind.utcs.toronto.edu> writes:
> Unfortunately the example doesn't work in several very useful
>situations: it will badly flub the common scripting idiom of
>'generate stuff | {while (read foo) {....}}', never processing
>most of the actual output.

My usual way through this situation has been to recode it as

for (i in `{generate stuff}) {...}

replacing ` with ``($nl) if I really want lines and not tokens. If the
input is big enough to cause problems for rc, I switch to awk, sed, or
whatever.  Complicated interactive scripts I usually write in awk/gawk.
This won't work to interact with a network connection, such as the news
and FTP snarfing scripts I use (see below.)

> In order to make this work, you need to find a utility that is
>guaranteed to read no more than the first line of standard input.
>Most utilities (eg awk) will happily eat an entire large buffer
>worth of standard input and then give you the first line back.
>This is unfortunate if you wanted to read the rest of the buffer's
>worth of input later.

I wrote a tiny C program "line" that reads a character at a time to ensure
that further input doesn't get eaten, and another one "spew" to handle
the "." on a line by itself ending a block of output protocol used by
news, mail, and others.  "line" wouldn't be necessary if news didn't
respond to article requests etc. with a response code line immediately
followed by the output.  You may notice that SMTP/NNTP don't put the
server in this situation...